Sulphuric-acid manufacture



GQ FL HUET..

SULPHUPJC ACID MNUFCTUHE.

APNIC/m0." FILED MAY 9. 1919.

Pateme May 9, i922,

INVENTR @am/@4L F. HMA/! Be it known that HUET, GF ATLANTA., GEORGIA., ASSIGNOR, BY MESNE ASSIGNMENTS, TO

JDEL' HUET, OF ATLANTA, GEOEGIA...

Semeraro-nein nianureorurn.

Applicaten led. 'may 9,

To @ZZ whom it may concern l. Grenen lf. liner, a citizen. of the AUnited States, residing at Atlanta, in the county of Fulton and State of Georgia, have invented certain new and useful improvements in Sulphuric-Acid Manu# l facture, ot which the following is a specifica ticularly this invention relates to vantages the y 'conmanying drawing.

tion, reference being had therein to the ac- 'lhis invention relates to sulphuric acidI manufacture and more particularly involves the, novel methodor system of manufacturing sulphiiric'acid, and an apparatus capable oi carrying o' auch method or system. The invention coi es an improvement in that part of the d or apparetus which utilizes snlt'nr dioaid gras, that is following the actual bnrningoi' the brirnstone or other suli'nr containing material, orl feeding' of sulfur dioxid 'from other source. More par.-

the action within or intermediate the Glover tower and the first: of the lead chambers, or these and the conszerter, and. the interaction and interconnectien as between. these portions of the plant. The main objects are to improve efficiency, increase output and render more uniform and reiiable operation and pros duction ot a `given plant. To the attainment ci these objects and adpresent invention consists Vin the novel method, system and apparatus d the novel features of procedure, operation, combination, arrangement, and details there` of herein illustrated, described or claimed.

Fig. i shows more or less diagrammatically 'a side elevation ofanentire sulphuricl acid rnanufacturing plant, in which the principles of' the present invention are en bodied or can be practiced.

2 is a similar view 'on' an enlarged scale of the particular' portion of the appart of the ap- Specification of Letters Patent.

called Gay-iliussac tower oaratus to which the present iniprovernent 1, the operations Patented May 9, i922..

191s. Serin no. 'senses hot condition, and comprising principally sulfur dioxid, pass through a flue B into the lower end of the so-called Glover tower C, above which is a nitrogen supplying vessel D. After treatment inthe Glover tower the gasespass therefrom successively through the leady chambers or acid chambers E, F, (i, etc., and thence into the base ofthe sol, the function of which is well understood and forms no part p of the presentsinvention. In the passage or flue E between the Glover tower and the irst chamberis shown an exhauster E2.. Pipes l1" constitute exits forthe first chanhber E, conducting; the gases onward to the second chamber F. l

A converter J is shown of the general type 70 known as the Pratt converter, this having.' avflue or pipe J" leading to it from .thev irst chamber E, and one or more compartments or -cones J2, within which liquid may -be sprayed, as usual in such converters. rom. the outlet at the top oi the converter J passes pipe J3, carrying the gases hack to recirculate. Heretof'ore' the passage J3, has been extended, as'indicated in dotted lines at J, so as to conduct the gases to the exhauster, and thence to the first chamber. in the present invention, however, the' very important improvement is introduced in eliminating the extension J, and instead continuing the exit pipe J3 from the converter by a pipe ori passage il leading into the Glover tower Cy.' The arrangeinentgfunctions, operations nd importance of this feature will be elucid ed hereinafter. ln part the improvement may be availed of by carrying the exit iue J back into or consisting oi" zones o-o'peratiomor function, and, as willvbe explained, these zones C", C2, C3 and Ci'may be considered as fonrin number, the first. being the topmost and the last the lowermostfinterior portion 100 of the tower. 4

There. are various well known details of construction and operation ot' the Glover tower and other illustrated elements lwhich need not be described, but will be understood, these elements being shown only conventionally herein. The. construction and ope 'ation of the vessel D, which furtrioxid is smallin amount and immediately combines with steam to form sulphuric acid in the Glover tower, and therefore offers no particular problem and will be hereinafter ignored. The sulfur dioxid is required to be supplied with water and oxygen, tl1e^ ap1mrent reaction being SOZ-l-HzO-l-O equals HZSOH but, is well known, an intermediate iroduct, nitrosyl sulfuric acid, SOTOHND, hereinafter referred *tol as nitrosyl acid, must be produced by the aid of nitrogen oxids or nitric acid present or supplied through the vessel D, and the sulphuric 'acid condenses therefrom in the presence of water (steam) and oxygen.

.The best conditions for formation of nitrosyl acid fromsul'fur dioxid (SO2) and nitrous anhydride (N203) are low temperature, and large oxygen excess in the presence of sulphuric acid. These conditions exist in the upper part of the Glover tower,

where the cooled descending acid meets the rising sulfur ditxid, nitrogen oxids and oxygenyalso in the upper part of the chambers close to the water sprays therein and in the spray cones of the converter. In each of these apparatuses and-wherever sulphuric acid condenses from nitrosyl acid, nitrous oxid (N20) is released. It combines with oxygen to form nitrous anhydride, which later is recombined into nitrosyl acid, more particularly inthe Glover tower, the first chamber and the converter. The nitrogen compounds thus pass through a cycle, being used over and over, and finally recovered in the Gay-Lussac tower and usually returned to the vessel D over the Glover tower. As the outputot' any plant depends on the rapidity and extent oit formation ot nitrosyl acid, it is important to maintain the most favorable conditions for sucht'ormation throughout the plant. Therefore in the Glover tower yshould be maintained ample excess of oxygen, a full supply oit sulfur dioxid and a full supply of cool acid; steam being suliciently supplied by the concentrating effect at the lower part of the tower. Low temperature at the upper part of the l tower is also important. Substantially the same statement applies to the conditions in the lirst chamber and the converter,\ in each ot' which active circulation should be maintained to ensure thorough mixing and intimate contact.

The conversion of nitrosyl into sulphur-ic acid occurs in the Glover tower, the-chambers and the converter, the requisite conditions being that the nitrosyl acid be not too strong, that there shall be'suiciently high temperature and ample supplies oi sulfur dioxid and water witha small excess of oxygen. These conditions prevail in the lower part of the Glover tower, but not at the bottom, and in the portion of the chamber removed from the walls and sprays, and within the entire central or packed space of the Iconverter.

I have thus found that within the packed space of the (llover tower, there are virtually Ytour different zones cic action.

In the topmost zone C, which may be termed the absorption zone, nitrosyl acid is being continually formed by the absorption of nitric oxid, (N202, formed in the second zone from N20 released and rising 'from the third zone), together with the' sulphuric dioxid and oxygen entering from the burners, and steam from the bottom zone. The reaction is not a direct one, asthe nitric oxid is selectively rst converted into nitrous anhydrid and nitrous acid. The action, ot' course, is progressive, there being no definite lines of demarcation between the gether with 4)the nitrogen compounds added -at the vessel Dv The best results require that the products passing through the Glover tower be cooled to substantially a temperature slightly over 100 C., that being the best temperature for the gases passing to the chambers..

The nitrosyl acid thus formed is a heavy Vapor, which is absorbed by downcoining acid, and descends, ,finding its way down through the tower through the second to the third zone. It will be understood, of course, that the exit E from vthe top zone is constantly carrying oil gaseous produc-ts to the first chamber, but each portion of nitrogen within the Glover tower repeats its cycle of reactions numerous times before finally escaping, and passing with the uncombined sulfur dioxid, steam and oxygen to the chambers.

The second zone C2, which is substantially neutral or indifferent, is not a region of chief activity of any/,oi the processes"referred to. In -fact, the reduction of this kone is oi' no harm, but on the co.. trary its reduction by the enlargement of the adjoining zones, it that can be accomplished, tends to greater efficiency. Thus, by properly controlling the materials fed in at the top, the first zone'l can be maintained of maximum depth and volume and sufficiently cool throughout for the purposes of its reactions. .The third zone,

likewise, as has been explained, can be benei,

' ficially expanded, although there should refrom the third Zone is herev converted into VThe third zone Cv3` is the denitrajtion Zone; Here the nitrosyl acid becomes ldenitrated, 'thus forming sulphuric acid andreleasing nitrous, acid, Whichrises, as before stated, to 4the first zone.

This reaction, as before ex# plained, vdepends in part upon the high tem-- perature ofthe third sone. lt cannot commence until reaching a sufficiently hot strata. a The rising hot sulfur dioxid, oxygen and the steam driven oft' in the fourth Zone react with the downcoining nitiosyl acid, theresulting liquid, sulphuric acid, descending, and the Vaseous products rising to the upper zones. he importance will now beobserved .of extremely high temperature in the vgases` supplied to the Glo-ver tower. Increased temperature of the gases results in quicker den'itration and therefore more effective pro-V duction in lthe Glover towery ofsulphuric acid. The fourth or bottom Zone C* is the con-* centration zone, and functions to drive off from the descending sulphuricacid the water contained therein, which rises in the form of steam and is utilized in the. third and lfirst zones and in the first chamber, as'before explained. T he acid drawn off at the baseof the Glover tower is extremely concentrated, and is of great value commercially, for 'direi-t, use in many chemical processes, and is avail able foi` use in the recovery processes in the Gay-Lussac tower.

The gases, including sulfur dioxid, which pass along from -the Glover tower to the firstchamber, are thoroughly mixed and .per-

. mitted to thoroughly combine in the latter,

going through a cycle similar to that alreadyl explained. The condensed sulphuiic acid is collected in the water pan at the bottoni, while the nitrogen oxids rise and at the cooler parts of the chamber recombine into nitrosyl acid, 'resulting in further condensation ofsulphuric acid. The carrying on of these cycles and the mixing of the gases in thefirst chamber are enhanced by maintaining the circulation therein such as indicated in Fig. 3; The incoming gases are seen to pass along the center and reversely at the sides, forming two long eddies, which carry the gases altei-,

-eii

nately to and from the water cooled parts of the chamber.

The reactions in the iii-st chamber are rendered more active and thorough by the recirculation of the gases through the use of the converter. After an amount of sulphuric vand thethorough mixing effected therein in the presence of a'large area of packing sui'- faces, with which the nitrosyl acid contacts.

Thespent gases,. that is, having lowest SO-2'-coiitent, finally pass outfrom the first chamber bythe exitpipes F, F", after hav- `i'ngfooinpleted their travel, so that the maximum" production isfsejcuredgbefore the gases arecarijied 'to the second chamber. ln that and subsequent .char'nbeijs the condensation of sulphuric'acid is much Ireduced, because ofvthe 'exhaustion of the necessary vingre- I -dients 'and 'the lowered temperature, but'the action continues throughout the successive dioxid is used. The" irst .chamber yields'a considerably larger amount lof acid than 4.any of -the subsequent ones, especially asl its length .and 'space is' usually considerably larger, and the "acid.making-elements are. richer, and thecirci'ilat-ion.more"active; so

,that in the later chambers.theconversion of4 sulfur dioxid to nitrosyl acid and the latter to sul phuricl acid for the purpose of efectingthe highest possiblefrecovery ofy sul- Referring again to '.tli'ei'converter, this is .fed by the gases from tlicllexti'eme end of the first chamber, which on entering the con- 'cliainbers'un'til substantially allthe sulfur ioo verter are saturated by the sprays, being cooled to the' critical temperature for forma-- tion of iiitrosyl acid, and containing the propel components for thatreaction. -The-I nitrosyl acid thus formed enters the body of;

the converter, which, being not .only quartz' packed, but brick linedholds considerable heatand serves tov reheat the gases, the nitrosyl acid taking upA oxygen. l Nitrous oxid is thus released while the sulphiiific acid runs down as a liquid and is drained away.

As before stated, heretofore the` nitrous oxid from the converter, also the inert nitro-` gen and the residues of sulfur dioxid, oxygen and water vapor have been carried from the top of the converter to the. main flue leading from the Glover t owerwhere the same mix with the fresh gases from the Glover tower; so that they are used over and over again in the production of nitrosy-l and then sulphuric acid, and finally are'conducted to the.

front end of the first chamber, so that part of the nitrogen elements are recirculated and used again and again.

In any given part of the plant the efficiency of sulphuric acid production depends on three considerations, the richness of the gases, including vapors, in the necessary ingredients, proper temperature conditions and thorough mixing. The conditions in the Glover tower aredili'er'ent from the chambers, the cycle or production being much more rapid. This is partly because the gases are much richer, therebeing unlimited quantities of oxygen and water vapor and plenty of nitrous oxid yielded by the denitration in the third Zone. Also because of the great absorptive capacity of the first zone afforded by the cooled acid, which is put down into the top end of the Glover tower, giving the best conditions for the absorption by the incoming' acid of the nitrogen oxids. Also because of the greater temperature range in the Glover tower, one extreme being cool enough to produce nitrosyl sulphur-ic acid and the other hot enough to condense sulphuric acid therefrom.

According to the present invention, as before stated, the nitrogen oxids and the residualgases from the top of the converter are carried back, not merely to the irst chamber, but to the Glover ,tower and caused to enter the upper part thereof. Preferably this recirculation inlet leads into the second -or neutral zone, as indicated in Fig. 2. The

important results of this improvement lrequire the following explanation, which will b e understood to those skilled in the art -after consideration of the conditions hereinbefor'e already explained.

rlhe residual nitrogen oXids 'from the con` verter can work to much greater effective- .nes'sin the absorption Zone of the Glover tower than in the first chamber, because 1n the Glover tower the cycle of reactions is moreaotive and rapid. In other words, the oXids are set into operation where their i work is most effective.

Moreover, .the gases from the converter are relatively cool, and their action thereL fore in the first zone of the Glover tower is 'to increase the cooling efect, and thereby enlarge the depth and space of the first Zone at the expense of the second or neutral zone. l This increases `Vthe absorptive capacity of the Glover tower, correspondingly increasing-' the production of nitrosyl, and

therefore of sulphuric, acid.- This, as already stated, is of great advantage, especially as the acid produced in the Glover tower is of the greatest value.

A resultant advantage is as follows. The increased utilization of sulfur dioxid in the Glover tower would at first sight seem to reduce the quantity or percentage thereof which passes on to the first chamber, the converter, etc. The capacity, however, of these elements of the plant remains as high as before. W e may, therefore, increase the rate of supply of burner gases, or other SQ.,

.nitrogen content.

'crease the space of the first or absorption regulating the passage of gases through the liue E', and the increased flow of gases into the Glover tower is attained by opening suoli damper.

It will be perceived from these conditions that, owing vto the increased acid producing reactions in the Glover tower, and also to the increased rate of supply of sulfur dioXid thereto, it is possible to put down into the topof the Glover tower a greater quantity of the cool and weak acid with This again tends-to inzone, giving better eli'iciency. Gwing to the same cause, more water vapor is driven oil'l in the third zone and carried upward-and on to the first chamber. A more evenly balanced gas mixture is thus furnished to the front end of the firstv chamber, as regards the percentages of the necessary components of nitrosyl acid. This gives more efective reactions within the first chamber.

The net results, therefore, of the described improvement include materially increased production of acid in the Glover tower, and increased production as well in the first chamber, both of these valuable results being secured without increased consumption of nitrating material. The acid production in the second and subsequent chambers, it should be stated, continues substantially unchanged. Therefore, with a given plant and with a given nitre consumption, that is, given in amount, and therefore reduced in percentage to the acid production, a materiallygreater sulphuric acid production is attainable, and the operations are excellently reliable in their eiiiciency and uniformity.

It will thus be seen that I have described an example of a process or system and ap paratus for the manufacture of sulplturic acid embodying the principles of the present invention. Since various matters` of procedure, combination, arrangement, construction, detail and other features may be vari ously modiiied without departing from the underlying principles of the invention, there is no intention to limit the invention to such features except in so far as set forth in the appended claims.

Nhat is claimedis:

1. The method of sulphuric acid manufacture comprising passingv gases from the Glover tower through the chamber,. thence through a converter and returning the same from the converter to the upper part of the Glover tower.

2. The method of sulphuric acid `inanufao-l Glover tower through a chamber and thence beck into an intermediate part of theGlover tower for recirculation.

3. Apparatus for sulphuric acid manufac- 5 ture, comprising a Glover tower, a chamber, passages from the Glover tower to the Chamber, and passages from said chamber leading to a point above the base of the Glover tower for recirculation intol the Glover tower and chamber. l i 1U n testimony whereof, have affixed my signature hereto.

GEORGE it HUET. 

